Ignite Ducati's Ben Spies has been ruled out the Jerez MotoGP round after doctors advised he take three weekends off following the stabbing pains he experienced during morning warm-up at Circuit of the Americas.

The Texan rider said it had felt like he had been stabbed and medics believe the pains are more serious than first thought. He will now undergo intensive rehabilitation to alleviate the strain in his pectorals and back muscles.

"Despite the constant improvement in the condition of his shoulder after recent surgery, Ben still needs further intense work to build up his muscle, and to acquire the necessary strength which will enable him to endure the stress during the race," said a team spokesman.

"Therefore the therapy will be different to what he has done so far, focused on limb mobility, thanks to his better physical condition. These three weeks of therapy will allow the Texan to be back for the Le Mans race."